Impeller assembly

ABSTRACT

An impeller assembly having a housing supporting a rotatable impeller. The housing has a bottom entrance opening and a top exit opening separated by a curved back wall. A liner of low friction and abrasion resistant plastic material located adjacent a portion of the inside of the back wall prevents material buildup on the back wall. The liner is removeably mounted on the housing so that it can be replaced without taking the housing apart. The impeller has a plurality of pivoted paddle assemblies. Each paddle assembly has a body carrying a generally U-shaped liner of low friction and abrasion resistant material to minimize the collection of material on the paddle assemblies. The housing includes a knife adjacent the entrance opening. The body of the impeller assembly has a transverse lip that moves in close relation relative to the knife to cut material.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.542,538 filed Jun. 25, 1990, now U.S. Pat. No. 5,035,317. U.S.application Ser. No. 542,538 is a division of U.S. application Ser. No.388,140 filed Aug. 1, 1989 now U.S. Pat. No. 4,964,502.

TECHNICAL FIELD

The invention relates to impellers for use with material handlingmachines, such as silo unloaders, material blowers, crop cuttingmachines, lawn mowers, scattering unloaders, and beet toppers to pick upand convey particulate materials to a selected location. The impellershave rotating discs carrying pivoting paddles located within housingsfor throwing particulate material out of the housings into materialdischarge chutes. Impellers of this type are used in top unloading silounloaders.

BACKGROUND OF INVENTION

Material throwing impellers having pivoting paddles are used in silounloaders to pick up silage and haylage and throw these materials intotower silo chutes. An example of an impeller for a silo unloader havingpivoted paddles is shown by Hansen in U.S. Pat. No. 3,589,500. Thepaddles have generally V-shaped metal bodies pivotally connected to arotor mounted on a drive shaft. The shaft is rotatably mounted on ahousing having a bottom entrance opening and a top exit opening. Thepaddles move in close relationship to a sheet metal back wall leadingupwardly to the exit opening. The paddles as they pick up the materialimpact material on the lower entrance plate and back wall and otherinside surfaces of the housing. The material being wet has gum andstrong adhesive characteristics which causes the material to collect onthe walls of the housing. The buildup of a material on the housing wallsinterfers with the rotational movement of the paddles and increases thepower required for rotating the impeller. The buildup of the gum-likematerial on the housing and paddles also decreases the throwing abilityof the paddles. The material must be periodically removed from theinterior of the housing which is a difficult and time consuming task. Itis common practice to wash the inside of the impeller housing andimpeller paddles with water to remove the material collected on themetal surfaces of the housing and impeller paddles. The machine must beshut down and manually serviced. A water hose must be hauled up into thetower silo so that the operator can flush out the machine to removebuildup of material from the operating parts thereof. The impellerhousing and paddles of the invention have substantially reduced materialcollection problems and eliminated the need to wash the machine tomaintain efficient operation. The power required to operate the silounloader has also been reduced.

Silo Unloader impeller housings are fabricated sheet metal structureshaving material inlet and outlet openings. An impeller having pivotedpaddles is located within the housing. An example of a one-piece silounloader impeller housing is disclosed by F. E. Buschbom in U.S. Pat.No. 3,221,904 issued Dec. 7, 1965. This housing cannot be taken apart toservice and clean the interior thereof. Silo unloader impeller housingshave been made in two sections to aid in assembly of the housings. Thesehousings have a top section having horizontal members secured to abottom section generally along the horizontal plane of the axis ofrotation of the impeller. Major parts of the silo unloader must beremoved to take the housing apart. This is a substantial project and isnot normally done to clean out the impeller housing and impellertherein. The impeller apparatus of the invention has overcome thesedisadvantages of the prior silo unloader impeller housings.

SUMMARY OF INVENTION

The invention broadly relates to a material handling apparatus formoving bulk material including particulate material to a selectedlocation. The material handling apparatus has a housing surrounding achamber having an inlet opening and an outlet opening spaced from theinlet opening. The housing includes a wall section having an insidesurface extended between the inlet and outlet openings. A low frictionand abrasion resistant member is located in surface engagement with thewall section to minimize collection of the material on the insidesurfaces of the housing. The low friction and abrasion resistant memberis removably retained on the housing so that it can be replaced with anew low friction and abrasion resistant member. The housing includeswalls having grooves for accommodating opposite edge portions of theabrasion resistant member to hold the member on the wall section of thehousing. The housing has a door which can be opened to provide access tothe abrasion resistant member to facilitate its removal from andinsertion into the housing. The member is a one-piece plastic liner ofultra high molecular weight and high density polymer. The material canbe a polyethelene impregnated with abrasion resistant material, such asceramics.

An impeller located within the chamber is operable to move materialthrough the housing. The impeller has a plurality of paddle assembliesthat have outer ends that move in close relationship to a knife mountedon the housing adjacent the inlet opening. The knife has a materialcutting edge located in close relationship to the path of movement ofthe outer transverse edges of the paddle assemblies to cut materialmoved by the paddle assemblies as the material enters the housing. Thisminimizes the amount of material that can collect on the knife andreduces the power required to operate the silo unloader.

Each impeller paddle assembly has a liner of low friction and abrasionresistant plastic mounted on the leading sides of the body of the paddleassembly. The liner can be turned in end-to-end or removed from thepaddle assembly and replaced with new liners. In one form of paddleassembly the body has a recess or pocket on the leading side thereof toaccommodate the liner. A fastener, such as a nut and bolt assembly,holds the liner on the body. The body has a transverse lip at its outerend which extends to the outer face of the body and forms therewith atransverse edge that moves in close relation with respect to the knifeedge to cut material.

The housing has a top cover that can be removed without disassemblingthe impeller or other parts of the machine. When the cover is removedthe paddle assemblies can be serviced in a minimum time and effort. Thecover has a forward lip and side walls that cooperate with holdingflanges on the housing. Removable fasteners secure the cover to thehousing.

DESCRIPTION OF DRAWING

FIG. 1 is a fragmentary side elevational view of a silo unloaderimpeller assembly of the invention;

FIG. 2 is a rear elevational view of the impeller assembly of FIG. 1;

FIG. 3 is a sectional view taken along the line 3--3 of FIG. 2;

FIG. 4 is an enlarged vertical sectional view of the back of theimpeller housing showing the removable liner;

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4;

FIG. 6 is an enlarged sectional view taken along the lines 6--6 of FIG.2;

FIG. 7 is a plan view of a liner apart from the impeller housing;

FIG. 8 is a side view of FIG. 7;

FIG. 9 is an end view of FIG. 7;

FIG. 10 is a sectional view taken along line 10--10 of FIG. 7;

FIG. 11 is a perspective view of a paddle assembly of the impeller shownin FIG. 3;

FIG. 12 is an enlarged outer end view of the paddle assembly of FIG. 11;

FIG. 13 is an enlarged side elevational view of the paddle assembly ofFIG. 11;

FIG. 14 is a sectional view taken along the line 14--14 of FIG. 12;

FIG. 15 is an exploded perspective view of the paddle assembly;

FIG. 16 is a perspective view of a modified paddle assembly usable withthe impeller shown in FIG. 3;

FIG. 17 is a top plan view of the paddle assembly of FIG. 16;

FIG. 18 is a bottom plan view of the paddle assembly of FIG. 16;

FIG. 19 is a side elevational view of the left side of the paddleassembly of FIG. 16;

FIG. 20 is an end view of the inner end of the paddle assembly of FIG.16; and

FIG. 21 is an end view of the outer end of the paddle assembly of FIG.16.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 3, the impeller assembly of the inventionindicated generally at 10 is part of a top unloading silo unloaderhaving material collectors or augers 13 operated to move material fromthe top surface 17 of the material in the silo toward impeller assembly10. The leading auger 13 has a short reverse flight 14 operable to movethe material to radial flipper blades 16 that kick the material into theinlet opening of impeller assembly 10. Impeller assembly 10 is hereindescribed as incorporated into a top unloading silo unloader of the typedisclosed by F. E. Buschbom in U.S. Pat. No. 3,232,456 issued Feb. 1,1966. The invention incorporated in impeller assembly 10 is applicableto other agricultural, industrial, and residential equipment includingbut not limited to material and snow blowers, crop cutting machines,lawn mowers, scattering unloaders, beet toppers, pump and relatedequipment used to move liquids and particulate material to a selectedlocation.

Impeller assembly 10 has a housing indicated generally at 18 comprisingparallel flat side walls 19 and 21 secured to a convex curve rear wall22. Rear wall 22 has side flanges 23 and 24 that extend over outer edgeportions of side walls 19 and 21 and are secured thereto by welds or thelike. Side wall 19 has a bottom edge 25 aligned with a bottom edge 26 onside wall 21 forming a bottom or material inlet opening 28. Locatedabove rear wall 22 is an upright back wall 29 secured to side walls 19and 21. A lower front wall 30 is secured to front edge portions of sidewalls 19 and 21 above the front end of material inlet opening 28. A topfront wall 31 facing back wall 29 secured to side walls 19 and 21 formsan upright neck having an outlet or top opening 32. The neck is inclinedupwardly and outwardly at a slight angle from the vertical of about 3degrees to locate the collector augers 13 at a slight angle toautomatically maintain an upward central cone shape of the top surfaceof the material in the silo. The neck can be maintained at other smallangles to achieve the upward central cone shape of the top surface ofthe material in the silo.

The top front wall 31 is circumferentially spaced from the lower frontwall 30 providing a top opening into the inside chamber of housing 18.This opening permits admittance to impeller 100 within housing 18without taking the machine apart. Repairs and adjustment of impeller 100and paddle assemblies 103, 104 and 105 can be made with minimum time andeffort. The liners 123 and 223 can be removed from the paddle assembliesand replaced with new liners without removing them from the impeller.

A discharge chute (not shown) located above the neck directs thematerial from housing 18 toward a silo chute or other selected location.Angle members 33 and 34 secured to opposite sides of the neck areadapted to be attached to additional silo unloader structure such as atransition assembly providing an electrical connection to an electricmotor (not shown) for driving the silo unloader.

The top opening of housing 18 is closed with a cover indicated generallyat 36. Cover 36 can be removed from housing 18 to provide access toimpeller 100 without disassembling the silo unloader. Cover 36 hasparallel flat side walls 37A and 37B joined to a convex curved top wall38. The pair of upwardly directed ears 39 and 41 having aligned holes attheir outer ends are secured to side walls 37A and 37B and extendoutwardly from top wall 38 are used to accommodate a pin so a cablehoist can be used to lift the entire silo unloader. The outer portion oftop wall 38 has an angle member 42 that fits on top of a bracket 43secured to lower front wall 30. A plurality of nut and bolt assemblies44 releasably secure angle member 42 to bracket 43. The lower linearedges of side walls 37A and 37B are located adjacent side flanges 46which form grooves 47 along walls 19 and 21 for the lower edges of sidewalls 37A and 37B. The lower edges of walls 37A and 37B of cover 36 lapover side walls 19 and 21 and fit into the grooves of flanges 46.Upwardly directed end flanges 48 extended from the center section ofhousing 18 toward upper front wall 31 have grooves 49 accommodating rearedges of walls 37A and 37B. The top of cover 36 has a rearwardlydirected lip 35 that fits under a ledge or shoulder 40 secured to topfront wall 31 whereby cover 36 is located on side walls 19 and 21 andengageable with front end walls 30 and 31 to enclose the top of housing18. Cover 36 can be removed from housing 18 by removing nut and boltassemblies 44 and the nuts thereon and lifting cover 36 from side walls19 and 21 and moving lip 35 from ledge 40.

Referring to FIGS. 3, 4, and 5, an elongated arcuate liner, indicatedgenerally at 51, of abrasion resistant plastic material having a lowcoefficient to friction is located in surface engagement with the insidesurface of rear wall 22. Liner 51 is an elongated sheet member ofbendable abrasion resistent plastic having a low coefficient of frictionthat promotes material flow and eliminates material build up in thehousing. An example of a suitable abrasion resistant plastic material isan ultra high molecular weight and high density polymer. This materialis highly abrasion and impact resistant which has minimum wear caused bysliding abrasion. The plastic is self lubricating with a very lowcoefficient of friction, and does not absorb moisture which reducessticking and freezing of material on its surfaces. The plastic isresistant to moisture, acids and chemicals, and will not rust orcorrode. The wear resisting features of the plastic is enhanced withimpregnated abrasion resisting material or particles 72, such asceramics and like materials, as shown in FIG. 10. An example of asuitable plastic is a polymer identified by the trademark TIVAR-88available from Polytech Industries, Inc., Monticello, Ga. 31064.

As shown in FIGS. 7 to 10, liner 51 is a one-piece elongated, flat,rectangular sheet member having opposite transverse ends 52 and 54 andlinear opposite parallel side edges 56 and 57. The side surfaces 69 and71 are smooth and continuous. The sheet member has uniform thickness andis bendable in the transverse direction to form a broad arcuate shape.An example of liner 51 for a silo unloader impeller housing is aone-piece plastic sheet member having a uniform thickness of 1/4 inch, awidth of 51/8 inches, and a length of 201/4 inches. Liner 51 can haveother sizes to fit into different shapes and sizes of impeller housing.The plastic material is a low friction and ultra high molecular weightpolyethyene impregnated with ceramic particles.

Liner 51 as shown in FIG. 4 and 5, has lower transverse edge 52 bearingagainst a transverse plate 53 secured to the lower end of rear wall 22across the inner end of the bottom inlet opening 28 of housing 18. Plate53 is a right angle member having a portion projected inwardly from backwall 22 to provide a stop for the lower transverse edge 52 of liner 51.As shown in FIG. 4 and 5, plate 53 has a second knife portion 55 thatprojects downwardly and inwardly generally concentric with the axis ofrotation of impeller 100. As shown in FIG. 3, liner 51 and back wall 22have a radius of curvature that is greater than the outer path ofimpeller assemblies 103, 104 and 105 to permit free flow of material andair along liner 51. The minimum clearance of impeller assemblies 103,104 and 105 with housing 18 is adjacent knife portion 55 to facilitatethe cutting of the material. As shown in FIG. 5, knife portion 55 has afront V-shaped sharp edge. The edge converges at an angle of 30 degreesfrom a transverse line. Other angles can be used for the sharp edge ofknife portion 55. The knife portion 55 reduces the amount of materialthat may collect on plate 53. The use of a flat plate without a knifeacross the lower end of back wall provides a material collection surfacethat accumulates material which creates resistance to the rotation ofimpeller 100. This increases the power needed to effectively rotateimpeller 100. The knife portion 55 projects down over plate 53 and has asharp edge that cuts material so that the material does not collect onplate 53. Thus, less power is needed to effectively operate the impeller100.

Liner 51 extends upwardly from bar 53 along the inside surface of backwall 22 to a transverse edge 56 at the bottom of back wall 29. Thetransverse upper edge 54 of liner 51 is located adjacent edge 56 therebypositioning liner 51 along the inside of back wall 22. The liner 51 isbent into an arcuate shape with the back surface 71 in continuoussurface contact with the inside face of back wall 22. Liner 51 is heldin this position to prevent material from collecting behind liner 51 andchanging the location of front surface 69. Surface 69 extends frombottom end 52 along an arc above the horizontal plane of the axis ofrotation of impeller 100. The radius of this arc is greater than theradius of outer edges of impeller 100. Bolts, rivets, and pins are notused to secure liner 51 to back wall 22 as these fasteners do notprevent material from working behind liner 51 and do not maintain asmooth continuous arcuate outer surface on liner 51.

As seen in FIG. 6, the opposite side edges 56 and 57 of liner 51 arelocated in grooves or tracks 58 and 59 between the outer edges 61 ofside wall 19 and back wall 22 and the outer edge 62 of side wall 21 andback wall 22. Edges 56 and 57 have a sliding tight fit in grooves 58 and59 so that liner 51 self seals on back wall 22 preventing material fromgetting behind liner 51. Grooves 58 and 59 are arcuate tracks open totransverse bar 53 and extend upwardly therefrom along the curvature ofrear wall 22 to a movable door indicated generally at 63 for retainingthe upper end of liner 51 in alignment with back wall 29. Door 63 is agenerally flat plate having upright side flanges 64 and 66 thattelescope over the side edges of side walls 19 and 21. A hinge 67secures the bottom of door 63 to the top of rear wall 22 whereby door 63can be moved from a closed position, as shown in FIG. 1, to an openposition to provide access to the upper end of liner 51 to enable theremoval of liner 51 from housing 18. The upper end of liner 51 is movedoutwardly away from the lower edge 56 of back wall 22. An upwardlydirected pulling force is applied to liner 51 with the use of a grippingtool to slide liner 51 along grooves 58 and 59. Alternatively, a toolcan be inserted between liner 51 and back wall 22 to force or pop outliner 51 from grooves 58 and 59. A new liner can be placed along rearwall 22 by sliding the new liner along grooves 58 and 59 until lower end52 thereof engages the cross bar 53. The upper end of the new liner isthen placed in alignment with the lower edge 56 of back wall 29. Door 63is moved upwardly to its closed position. A latch 68 holds door 63 in aclosed position. Latch 68 can be released so that door 63 can be pivoteddownwardly to an open position.

Latch 68 has a catch member 73 connected to back wall 29 above door 63.A hook 74 pivoted to an over center lever 76 is mounted on door 63. Hook74 engages catch member 73 to hold door 63 shut. Lever 76 is moved up torelease hook 74 from catch member 73 so that door 63 can be moved to anopen position. Other types of latches and releasable fasteners can beused to hold door 63 shut.

As shown in FIG. 3, impeller indicated generally at 100 located withinthe housing chamber has a central generally triangular hub or disc 101secured to a power driven shaft 102. The three corners of disc 101 arepivotally connected to paddle assemblies 103, 104 and 105. Separate pins106, 107, and 108 pivotally connect paddle assemblies 103, 104, and 105to the three corner portions of disc 101 for limited swinging movementrelative to disc 101. Disc 101 has radial abutments 101A at each cornerthat limit forward pivotal movement of the paddle assemblies 103, 104,and 105 during rotation of impeller 100 in the direction of arrow 99.The centrifugal forces acting on paddle assemblies 103, 104, and 105pivot the paddle assemblies about pins 106, 107, and 108 in forwarddirections until they contact abutments 101A. The longitudinal planes ofthe leading faces of paddle assemblies 103, 104, and 105 are in generalradial alignment with the axis of rotation of impeller 100. These planesare rearwardly of the radial lines passing through pivot pins 106, 107,and 108. The center of gravity of each paddle assembly is rearward ofthe center of rotation of the paddle assembly. This relationship betweenthe center of gravity of the paddle assemblies substantially rigid intheir radial positions even at relatively low rotational speeds. Whenrelief of a paddle assembly is necessary, as when hard material entersthe inlet opening of the housing, the paddle assembly will swingbackward and ride over the hard material.

Paddle assemblies 103, 104, and 105 are identical in construction. Thefollowing description is limited to paddle assembly 103. As shown inFIGS. 7, 9, and 10, paddle assembly 103 has a generally trough shapethrowing body 109 joined to upwardly and inwardly directed arms 111 and112. Holes 113 and 114 in arms 111 and 112 accommodate pivot pin 106mounted on disc 101 to allow paddle assembly 103 to swing on disc 101.Arms 111 and 112 are laterally spaced from each other to accommodate acorner portion of disc 101. Body 109 and arms 111 and 112 are aone-piece cast metal.

Body 109 has a longitudinal base 116 having a flat leading surface. Arear boss or rib 117 is on the trailing side of base 116 adjacent theouter end 118 thereof. Boss 117 is additional weight at the outer or tipend of paddle assembly 103. End 118 has a flat transverse surface thatis parallel to the axis of rotation of paddle assembly 103 about pin106. Side walls 119 and 121 joined to opposite sides of base 116 projectforwardly and outwardly forming a generally U-shaped channel or recess122 on the forward or leading side of body 109. Recess 122 has aninwardly stepped outer section as seen in FIG. 15 open to the outer endof base 116.

A shoe or liner, indicated generally at 123, preferably of ultra-highmolecular weight polymer impregnated with abrasion resistant particlessuch as ceramics, is located in stepped section of recess 122 andsecured to base 116 with bolt 133 accommodating nut 134. Liner 123 is aone-piece abrasion resistant plastic having a low coefficient offriction that promotes material flow and eliminates material build up onliner 123 thereby reducing maintenance time and labor. The plastic is anultra high molecular weight and high density polymer, that has highlyabrasion and impact resistant characteristics that reduce wear caused bysliding abrasion. The plastic is self lubricating and has a lowcoefficient of friction, and does not absorb moisture which reducessticking and freezing of material on its surfaces. The plastic isresistant to moisture, acids, and chemicals and will not rust orcorrode. An example of a suitable plastic is a polymer identified by thetrademark TIVAR-88 available from Polytech Industries, Inc., Monticello,Ga. 31064.

Liner 123 has a generally flat bottom 124 located in surface engagementwith the forward side of base 116. Upwardly and outwardly direct sideflanges 126 and 127 are joined to bottom 124. Flanges 126 and 127, asseen in FIG. 12, have outer portions in tight surface engagement withthe forward sides of side walls 119 and 121. Side flanges 126 and 127have upper linear edges 128 and 129 that project above the op of the topedges of the side walls 119 and 121. Side flanges 126 and 127 being intight contact with side walls 119 and 121 prevent material from workingbetween liner 123 and body 109. Liner 123 has a flat outer transverseend 130 coextensive with the outer end 118 of body 109. End 130 has achannel shaped upper edge 130A that cooperates with the V-shaped edge ofknife portion 55 on rotation of impeller 100 to cut the material movedtoward knife portion 55 by the impeller. The coextensive end surfaces118 and 130 are spaced inwardly from inner surfaces 69 of liner 51during movement of paddle assembly 103 relative to liner 51. Anincreasing radial clearance between the arcuate section of inner linersurface 69 and the outer ends of paddle assemblies 103, 104 and 105enhances the efficient impeller operation of the impeller. This radialdistance can be adjusted to change the tip clearance as hereinafterdescribed.

As seen in FIG. 14, bolt 133 extends through a hole 131 in body 109 andcounter sunk hole 132 in liner 123. Bolt 133 is an elevator bolt havinga large flat head engaging the center of the bottom 124 of liner 123.Two nuts 134 engage the outside surface of base 116 to retain the clampforce of bolt 133 on liner 123.

Liner 123 can be removed from body 109 by removing nuts 134 from bolt133 and removing bolt 133 from body 109. A new liner can be placed intorecess 122 and attached to body 116 by fastening bolt 133 to the newliner and body 109. Bolt 133 locates the inner transverse end 130A ofliner 123 adjacent transverse shoulder 110 of body 109 therebypreventing liner 123 from turning on body 109. Liner 123 can be turnedend-for-end so that end 130A is the outer end coextensive with end 118of body 109. This increases the useful life of liner 123 as both ends130 and 130A can be located at the outer end of body 109.

Referring to FIGS. 16--21, there is shown a modification of the paddleassembly indicated generally at 203. Paddle assembly 203 has a generallytrough shaped thowing body 209 joined to upwardly directed and inwardlyextended arms 211 and 212. The arms 211 and 212 have extensions or ribs211A and 212A that are joined to the bottom of body 209. Arms 211 and212 have aligned holes 213 and 214 to accommodate a pivot pin to mount apaddle assembly 203 on the impeller disc. As seen in FIGS. 17 and 18,arms 211 and 212 are laterally spaced from each other an equal distancefrom the center line of the paddle assembly to accommodate a cornerportion of the impeller disc. The body 209 and arms 211 and 212 areone-piece cast metal.

Body 209 has a longitudinal base 216 supporting a rear boss or rib 217adjacent the trailing side of the body adjacent the generally flat outerend 218 thereof. The upper portion of end 218 has a lip with transverseedge 220 that serves as a cutting edge in cooperation with the theV-shaped edge of knife section 55. Boss 217 provides additional weightalong with the material of the lip having cutting edge 220 at the outeror tip end section of paddle assembly 203. End 218 has a flat transversesurface that is parallel to the axis of rotation of paddle assembly 203and an upper horizontal surface that forms the transverse cutting edge220. Upwardly and outwardly directed side walls 219 and 221 are joinedto opposite sides of base 216 to form with the lip a generally U-shapedrecess or pocket 222 on the forward or leading side of body 209. Pocket222 has an inwardly stepped outer section 222A that accommodates a shoeor liner indicated generally at 223. Liner 223 is an ultra-highmolecular weight polymer impregnanted with abrasion resistent particlessuch as ceramics.

A bolt 223 having a flat circular head and a threaded stem accommodatinga nut 234 is used to hold liner 223 on the body 209 within the pocket222A. Liner 223 has a generally flat bottom 224 located in surfaceengagement with the forward side of base 216. Upwardly and outwardlydirected side flanges 226 and 227 are joined opposite side of bottom 224and engage the inside surfaces of the side walls 219 and 221respectively. The flanges 226 and 227, as seen in FIGS. 16 and 17, haveouter flat edges 228 and 229 that are flush with the top surfaces of theside walls 219 and 221. The side flanges 126 and 127 are located intight contact with the side walls 219 and 221 to prevent the materialfrom working between liner 223 and body 209.

Liner 223 is a one-piece abrasion resistent plastic having a lowcoefficient friction that promotes material flow and eliminates materialbuildup on liner 223 thereby reducing maintenance time and labor andpower requirements of the impeller. The plastic is an ultra-highmolecular weight and high density polymer that is highly abrasion andimpact resistent thereby reducing wear caused by sliding abrasion of thematerials handled by the impeller. The plastic is self-lubricating andhas a low coefficient friction and does not absorb moisture whichreduces sticking and freezing of material on its surface. The plastic isalso resistent to moisture, acid, and chemicals and will not rust orcorrode. An example of a suitable plastic is a polymer identified by thetrademark TIVAR-88 available from Polytech Industries, Inc., Monticello,Ga. 31064.

Returning to FIG. 1, a generally horizontal rib 135 is secured to themid portion of side wall 21 to longitudinally strengthen side wall 21. Asimilar horizontal rib 136 is secured to side wall 19. An upwardly andrearwardly inclined angle member 137 is secured to side wall 21 aboverib 135. Angle member 137 extends generally normal to a radial line ofback wall 22 that extends from the middle of the curved section of backwall 22 to the axis of rotation of impeller 100. A similar second anglemember is secured to side wall 19. The angle members are supports forbearings 138 that rotatably accommodate shaft 102. A plurality ofgenerally flat shims 139 are located between bearing 138 and anglemembers 137 supporting the bearings. Bolts 142 and 143 secure bearings138 to angle members 137 and clamp shims 139 between bearings 138 andangle members 137. The number of shims can be selected to radiallyadjust gap 143, as shown in FIG. 3, between the outer or tip ends of thepaddle assemblies 103, 104 and 105 and inner surface of knife section55. The shims have open end slots that accommodate bolts 141 and 142 sothat a selected number of shims can be removed or added to provide forthe radial adjustment of impeller 100 within housing 18. The adjustmentcan be achieved without removing shaft 102 from bearings 138. A minimumof tolerance or gap between knife section 55 and the outer ends of thepaddle assemblies 103, 104 and 105 as they rotate within the housingimproves impeller and material cutting efficiency and prevents buildupand wrapping of material on the impeller assemblies. The impelleradjusting shims can be removed to permit bearings to be mounted directlyon the angle supports 137 and 137A. The impeller 100 located withinhousing 18 can be made during assembly at the factory to ensure a closeclearance between the outer ends of the paddle assemblies 103, 104 and105 and the knife section 55.

While there have been shown and described, preferred embodiments of theimpeller with a low friction and abrasion resistant liner and paddleassemblies with liners it is understood that changes in the structure,materials, and arrangement of structure can be made by those skilled inthe art without departing from the invention. The invention is definedin the following claims.

I claim:
 1. A paddle assembly for an impeller of a material handlingmachine comprising: a body having a leading side, arm means connected tothe body adapted to be attached to a movable member, said body having anouter end opposite the arm means and a recess on the leading side of thebody, a transverse lip at the outer end of the leading side thereof,said lip having a transverse cutting edge and a transverse wall inwardlyof the cutting edge, liner means of low friction and abrasive resistantplastic located in said recess, and means connecting the liner means tosaid body thereby holding the liner means in said recess.
 2. The paddleassembly of claim 1 wherein: said liner means has an outer end locatedadjacent the transverse wall of the lip on the outer end of the body. 3.The paddle assembly of claim 1 wherein: the body has a base and upwardlyand outwardly directed side walls joined to the base forming saidrecess, said liner means comprising a member having a generally U-shapedcross section of a size to fit into said recess.
 4. The paddle assemblyof claim 3 wherein: the liner means has opposite edges adjacent the sidewalls of the body.
 5. A paddle assembly for an impeller of a materialhandling machine comprising: a body having a leading side, arm meansconnected to the body adapted to be attached to a moveable member, saidbody having an end spaced from the arm means and a recess on the leadingside of the body the body has a base and upwardly and outwardly directedside walls joined to the base forming said recess, liner means of lowfriction and abrasive resistant plastic located in said recess, saidliner means having surfaces located is engagement with the base and sidewalls, and means connecting the liner means to said body thereby holdingthe liner means in said recess.
 6. The paddle assembly of claim 5wherein: said base has an outer end and said liner means having an outerend coextensive with the outer end of the base.
 7. The paddle assemblyof claim 5 wherein: the body has a transverse lip at the outer end ofthe leading side thereof; said lip having a transverse cutting edge. 8.The paddle assembly of claim 7 wherein: the lip has a transverse wall ofsaid recess adapted to be engaged by said liner.
 9. The paddle assemblyof claim 5 wherein: the means connecting the liner means to said bodycomprises a nut and bolt assembly extended through aligned holes in theliner means and base.
 10. The paddle assembly for an impeller of amaterial handling machine comprising: a body having a leading side, armmeans connected to the body adapted to be attached to a moveable member,said body having an end spaced from the arm means at a recess on theleading side of the body, the body has a base and upwardly and outwardlydirected side walls joined to the base forming said recess, liner meansof low friction and abrasive resistent plastic located in said recess,the liner means comprises a one-piece plastic member having a generallyU-shaped cross sectional shape of a size to fit into said recess, andmeans connecting the liner means to said body thereby holding the linermeans in said recess.
 11. The paddle assembly of claim 10 wherein: theliner means has opposite edges adjacent the side walls of the body. 12.The paddle assembly of claim 10 wherein: the liner means comprises aone-piece plastic member of ultra-high molecular weight polyethyleneimpregnated with abrasion resistant material.
 13. The paddle assembly ofclaim 10 wherein: the means connecting the liner means to said bodycomprises a nut and bolt assembly extended through aligned holes in theliner means and base.
 14. The paddle assembly of claim 10 wherein: saidbase has an outer end and said liner means has an outer end co-extensivewith the outer end of the base.
 15. The paddle assembly of claim 10wherein: the body has a transverse lip at the outer end of the leadingside thereof, said lip having a transverse cutting edge and a transversewall inwardly of said cutting edge.
 16. The paddle assembly of claim 10wherein: the liner has an outer end located adjacent the transverse wallof the lip.
 17. The paddle assembly of claim 10 wherein: the liner meanshas a central hole aligned with a hole in the base, and fastener meansextended through said aligned holes to connect the liner means to saidbody.